1. Field of the Invention
This invention relates in general to a printed circuit board terminal device and particularly to a terminal device suitable for use with a plasma display panel.
2. Description of the Prior Art
Plasma display panels of X-Y matrix type are known as means for displaying characters or images. An x-electrode group comprising the data electrodes comprise anodes to which high and low voltages are applied corresponding to the display data. A y-electrode group which are the scanning electrodes comprises cathodes which are scanned in line sequential manner with a native voltage pulse.
An inner drive circuit for such plasma display panels comprises shift registers 10A and shift register 10B and a drive stage for converting the serial display data into parallel data as illustrated in FIG. 1. However, if the integration density of the discharge electrodes is increased so as to improve the resolving power of a display panel, the number of stages of the shift register will be increased according to the increase in the number of anodes and the transfer speed of the shift register becomes inadequate.
In view of this fact, the display data is converted into two bit parallel data and then is supplied to parallel shift registers 10A and 10B as illustrated in FIG. 2. For this arrangement, the parallel output lines of the shift registers 10A and 10B must be alternately arranged so that they can be connected to extending portions of the anodes of the display panel as shown in FIG. 2. Electrical connections between the circuit and the panel is generally accomplished with a flexible printed circuit board on which drive ICs are mounted. For this reason, with the arrangement of FIG. 2, both surfaces of the printed circuit board must be provided with patterns and the inserting portion of lines must be formed using plated through holes which results in high cost and low reliability.
With the arrangement illustrated in FIG. 1 when the electrodes are arranged so that they have a very fine pitch between them, the pitch p of a connecting terminal 11 of a flexible printed circuit board will become so narrow to reach the limit of manufacturing as is illustrated in FIG. 3. For this reason the conductor lines 12 between an integrated circuit 10 and the terminal 11 must be formed so that the conductor lines extend out from at least two side portions as illustrated in FIG. 3. Therefore, the size of the flexible printed circuit board will be large as compared to the width W of the actual plasma panel.
Also, as illustrated in FIG. 4, since discharge load resistors R must be inserted in the lines 12 between the anode drivers and the anodes, the pattern pitch of the resistor attaching portion must be increased and therefore it is difficult to mount the anode drive circuit on the flexible printed circuit board which has the same size as the plasma panel.